The nucleoside phosphatase method as a marker for the recognition of the autochthonous plexuses in blood vessel walls and the possible connection of the latter with acupuncture mechanisms.

The innervation of the blood vessels of the palatal mucosa of the frog is investigated histochemically. Besides vaso-motor nerves, fibers from the autochthonous plexuses also invest the vessels. Electron microscope studies of the latter show them to be non-nervous in structure contrary to previous belief. It is suggested they may influence vessels in a humoral manner and possibly play a part in acupuncture effector mechanisms. The electron micrographs are considered to reveal structure previously designated "terminal reticulum".